Mike McLelland and his wife, Cynthia, were found shot to death Saturday in their house in rural Forney, about 20 miles east of Dallas. / Kaufman County website via Getty Images

by Donna Leinwand Leger, USA TODAY

by Donna Leinwand Leger, USA TODAY

As Texas mourned slain Kaufman County District Attorney Mike McLelland and his wife, Cynthia, Gov. Rick Perry announced a $100,000 reward for information that leads to the killer's arrest.

Perry, who spoke at a memorial service for the couple Thursday at the First Baptist Church of Sunnyvale in Mesquite, a suburban Dallas church, said the McLellands recognized the dangers of Mike McLelland's work. The death of McLelland's deputy, longtime prosecutor Mark Hasse, was "heavy on their minds and hearts," he said. Still, Perry said, McLelland's resolve to "do right" never diminished.

The McLellands were found shot to death Saturday in their house in rural Forney, about 20 miles east of Dallas. Their slayings, just two months after two men gunned down Hasse, have stunned the county of 105,000. Kaufman County Crimestoppers has offered a $100,000 reward in the Hasse case.

Police have not arrested anyone in the deaths of Hasse or the McLellands and are investigating possible links to the March 19 killing of Colorado prisons director Tom Clements. Texas deputies in a shootout March 21 killed former 211 Crew prison gang member Evan Ebel, a suspect in the killing of Clements and a pizza delivery man. Investigators have said the gun Ebel used in Texas killed Clements.

Police are looking for two felons, James Lohr, 47, and Thomas Guolee, 31, with links to the 211 Crew gang. Guolee's father's financée, Carla Perry, in Gleason, Wis., said they have not heard from Guolee since before Christmas. Perry said she met him only briefly years ago.

Guolee has "moved around a lot," she said. "I have no idea where. We don't even have a mailing address."

Guolee's father, Phillip Goulee, 54, said his son has been in and out of prison since he was 17, when he was caught in a car with others who had a gun and drugs. After serving a six-year stint, he returned to Wisconsin to live with his father.

"He said he wanted to get away from all that gang stuff," Phillip Goulee said. But Colorado arrested him again for violating parole by leaving the state, and he returned to prison for six more years, he said. "I blame this on their system," he said. "You don't kick him out after six years and say, 'Have a nice life.'"

Goulee said his son is unlikely to return to Wisconsin, "because he knows I'd turn him in."

Police have not said if they are investigating any link to the death of a West Virginia sheriff, Eugene Crum of Mingo County. He was shot Wednesday as he ate lunch in his patrol car. Police arrested Tennis Maynard, 37, who has no previous arrest record in the state.